1. Field of the Invention
This device relates to rotary fluid machines and more particularly to rotary fluid pumps and rotary fluid motors.
2. Prior Art
In the prior art there exist rotary fluid pumps and rotary fluid motors. Such pumps and motors employ a rotor which revolves within a chamber provided in a stator, and the rotor is provided with radially guided vanes which revolve with the rotor and pass along a path between opposite curved faces of the stator, as the vanes are held in positive engagement with the profile of the stator. Each chamber of the stator is provided with inlet and outlet ports.
However, such fluid motors or pumps suffer from certain disadvantages. In particular, they are very inefficient in a wear aspect, and additionally they are speed and torque restricted. The primary reason for inefficiency is the fact that in such prior art rotary fluid pumps and motors, the vanes rotate with the rotor, and their rotating mass creates a centrifugal force and a hoop stress. As a result, vanes and stator curved faces wear unequally, as their outer sides wear more than their inner sides, i.e., they can not perform their primary function, to seal equally. Furthermore, considering that the centrifugal force and the hoop stress are proportional not only to the square of the rotating speed, but also to the centroidal radius; hence, it is clear that the prior art rotary machines are restricted in their diameter size, i.e. torque efficiency. In addition, by all of the prior art rotary machines, vanes are passing the ports and this could cause breakage or injury to the sealing surface of the vanes.
Another disadvantage of the prior art rotary machines is the fact that none of them is with wear compensated vanes proportionally to the applied pressure of the working fluid. As a result, any changes in the pressure of the fluid will affect the sealing effectiveness, i.e., the over-all efficiency of the rotary machine. In addition, the prior art rotary machines are very fluid contaminations sensitive, because of the sliding type seal between vanes and the stator surface.
Representative examples of such prior art rotary fluid machines are shown in the following United States patents: U.S. Pat. Nos. 315,318; 1,249,881; 2,099,193; 2,280,272; and 2,382,259.